Entering the Republican National Convention to ebullient cheers, Rep. Paul Ryan stepped confidently into the national spotlight as his party's vice presidential nominee and promised that he and Mitt Romney would tackle the country's most difficult problems to fix the economy and create millions of new jobs.

The 42-year-old Ryan, speaking at the end of a long day of speeches and video presentations by the party's graying old guard, cut a dramatically youthful figure and vowed to heed the "the calling of my generation."

"Whatever your political party, let's come together for the sake of our country. Join Mitt Romney and me. Let's give this effort everything we have. Let's see this through all the way. Let's get this done," Ryan declared.

Ryan, known as an earnest policy wonk, gave a rousing address that targeted President Obama and repeatedly brought the Republican crowd to their feet. They were clearly delighted with Ryan's performance and the anticipation that he will be the one to go for Obama's jugular, a role that Romney has shied away from.

The Wisconsin congressman hammered Obama for failing to create enough jobs, chastised the current administration for focusing on health care at the expense of the unemployed.

"Right now, 23 million men and women are struggling to find work… Nearly one in six Americans is living in poverty… So here's the question: Without a change in leadership, why would the next four years be any different from the last four years," he asked.

"We have a plan for a stronger middle class, with the goal of generating 12 million new jobs over the next four years," he said.

The promise of jobs is one that other candidates have made. In 2008, Obama promised to "save or create" 2.5 million jobs. Instead, the economy and high unemployment rates have become the most vulnerable part of his administration.

Ryan kept up the assault, slamming Obama for racking up $5 trillion in debt and doing "nothing" about it.

"One president, one term, $5 trillion in new debt… Republicans stepped up with good-faith reforms and solutions equal to the problems. How did the president respond? By doing nothing, nothing except to dodge and demagogue the issue," said.

Ryan pummeled the president's signature health care program.

"Obamacare comes to more than 2,000 pages of rules, mandates, taxes, fees and fines that have no place in a free country. The president has declared that the debate over government-controlled health care is over. That will come as news to the millions of Americans who will elect Mitt Romney so we can repeal Obamacare," Ryan said.

Delegates to the convention hung on his every word, energized in a way no speak yet this week has managed to capture them

"The present administration has made its choices. And Mitt Romney and I have made ours: Before the math and the momentum overwhelm us all, we are going to solve this nation's economic problems. And I'm going to level with you: We don't have that much time. But if we are serious, and smart, and we lead, we can do this," he said.

Conservative Republicans who were lackluster in their support of Romney have embraced his running mate. Crowd size at events with Ryan in tow has dwarfed those at which Romney appears alone.

"He has an amazing ability to energize a crowd, while presenting the important facts so that people can reach a common sense conclusion about the changes needed in this country," Republican strategist Alice Stewart told ABC News.

Ryan wrote tonight's speech with help from some of the GOP'S best speechwriters. Matthew Scully, who wrote Sarah Palin's convention speech and was also George W. Bush's speechwriter, andl John McConnell, Dick Cheney's speechwriter, contributed to the address.

Before Ryan spoke, former Secretary of State Condoleezza Rice took the stage. Rice is the only senior member of the previous two Republican administrations to attend the convention.

Both former president George W. Bush and his father George H.W. Bush appeared in video tributes along with their wives, but were not in attendance. After reminiscing about their administrations and complimenting each other, the two former presidents said they were supporting Mitt Romney's bid for the White House.

"He's a good man," the elder Bush said.

Former Arkansas Gov. Mike Huckabee also addressed the convention earlier in the evening. Huckabee, a former evangelical minister, appealed to evangelical Christians, an important party bloc wary of Romney's Mormon faith.

"I care far less as to where Mitt Romney takes his family to church than I do about where he takes this country," he said.

Huckabee's comments come after Ann Romney also mentioned her husband's faith while addressing the convention on Tuesday, indicating a shift in the campaign's previous approach of avoiding direct references to Mormonism.